Question 1

Which of the following correctly lists the order of mitosis phases and matches each phase with its primary event?

Accepted Answer

Prophase (chromosomes condense), Metaphase (chromosomes align at the metaphase plate), Anaphase (sister chromatids separate), Telophase (nuclear envelope reforms)

Question 2

Which checkpoint in the cell cycle ensures that DNA has been accurately replicated before the cell enters mitosis, and what would likely happen if this checkpoint failed?

Accepted Answer

G2 checkpoint; the cell could enter mitosis with uncorrected DNA errors, leading to mutations

Question 3

Which of the following best explains why sexual reproduction leads to greater genetic variation than asexual reproduction?

Accepted Answer

Sexual reproduction includes crossing over, independent assortment, and random fertilization, all of which shuffle genetic material

Question 4

During meiosis, which event is primarily responsible for the creation of new allele combinations on the same chromosome?

Accepted Answer

Crossing over during prophase I

Question 5

A cell is observed to have chromosomes aligned in pairs at the metaphase plate. Which process is this cell undergoing, and what is the significance of this arrangement?

Accepted Answer

Meiosis I; allows homologous chromosomes to be separated, reducing chromosome number by half

Question 6

Which enzyme is responsible for synthesizing the new DNA strand by adding nucleotides to the 3' end during DNA replication?

Accepted Answer

DNA polymerase

Question 7

What does it mean that DNA replication is 'semiconservative'?

Accepted Answer

Each new DNA molecule consists of one parental strand and one newly synthesized strand

Question 8

Which of the following best describes the antiparallel nature of DNA?

Accepted Answer

One DNA strand runs 5' to 3' and the other runs 3' to 5'

Question 9

A mutation changes a codon from UAU (tyrosine) to UAA (stop codon). What type of mutation is this, and what is its likely effect?

Accepted Answer

Nonsense mutation; results in premature termination of translation

Question 10

Which of the following statements correctly compares transcription and translation?

Accepted Answer

Transcription synthesizes RNA from a DNA template, while translation synthesizes protein from an RNA template

Question 11

A scientist observes Okazaki fragments during DNA replication. On which strand and in what direction are these fragments synthesized?

Accepted Answer

Lagging strand; 5' to 3' direction in short segments

Question 12

Which of the following is a disadvantage of asexual reproduction in a rapidly changing environment?

Accepted Answer

It produces genetically identical offspring, reducing adaptability

Question 13

If a mutation occurs during DNA replication and is not corrected, which of the following is a possible consequence for the organism?

Accepted Answer

The mutation may be silent, harmful, or beneficial, depending on its nature and location

Question 14

Which process during meiosis is responsible for the independent segregation of maternal and paternal chromosomes into gametes?

Accepted Answer

Independent assortment during metaphase I

Question 15

A cell is in Gap 1 (G1) phase. Which of the following best describes what is happening in the cell?

Accepted Answer

The cell is growing and carrying out normal metabolic functions

Question 16

Which enzyme joins Okazaki fragments together during DNA replication?

Accepted Answer

Ligase

Question 17

A patient is diagnosed with a genetic disorder caused by a frameshift mutation. Which of the following best describes a frameshift mutation?

Accepted Answer

A mutation that inserts or deletes nucleotides, altering the reading frame

Question 18

Which of the following scenarios best illustrates the importance of the M checkpoint during mitosis?

Accepted Answer

A cell ensures all chromosomes are properly attached to spindle fibers before anaphase

Question 19

Which of the following is true regarding the products of meiosis compared to mitosis?

Accepted Answer

Meiosis produces four genetically unique haploid cells; mitosis produces two genetically identical diploid cells

Question 20

Which of the following best explains why random fertilization increases genetic variation in sexually reproducing organisms?

Accepted Answer

Any sperm can fertilize any egg, combining different genetic backgrounds

Cell Division, DNA Replication, and Gene Expression: Study Notes

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